SOFA Issue: 2015-02-09

This is the master page for the SOFA Libraries Issue 2015-02-09 which was
released on 2015-02-09 at 12:00:00 UTC. From here you can find your way to all
the resources comprising this Issue, including notes and source download
pages. A summary of changes for the new
release is available.

PLEASE NOTE: The Fortran and ANSI C versions of the SOFA Libraries have
been unified and will be referred to as the eleventh release of SOFA.

Fortran 77 release

Issue 2015-02-09 is the eleventh release of
the SOFA Library for Fortran 77, revised on 2015-04-02.
Documentation for this Fortran 77
release is available.

ANSI C release

Issue 2015-02-09 is the eleventh release
of the SOFA Library for ANSI C, revised on 2015-04-02.
Documentation for this ANSI C
release is available.

A note concerning IAU precession-nutation models

This SOFA release contains support for the IAU 2006 precession model, used
in conjunction with the existing IAU 2000A nutation model.

The IAU 2006 precession and IAU 2000A nutation are completely separate
standards, and associated with the IAU 2006 precession is a transformation to
be applied to the IAU 2000A nutation in order to make them match. The mismatch
that this transformation eliminates stems partly from the purely geometric
effect of the revised obliquity and partly from phenomena taken into account in
the IAU 2006 precession that are absent from the IAU 2000A nutation. In the
present era the adjustments are very small (microarcseconds) and are of formal
rather than practical significance.

Certain SOFA subroutines apply this transformation, and have names that
include the string "06A" as shorthand for "IAU 2006+2000A precession-nutation".
It is important to understand that this is done simply to keep names concise
and does not imply the existence of "IAU 2006A nutation". Care has been taken
in the program comments for each affected SOFA routine, and in the other
documentation, to keep IAU 2006 precession, IAU 2000A nutation, and the
matching transformation all separate.